The prior art discloses bars of various constructions which extend across the joints between adjacent concrete slabs to provide vertical shear stress load transfer. Dowels are smooth bars, not bonded to the concrete, and allow movement of the concrete with respect to the bars so that upon shrinkage of the concrete, the joint may open. Wide gaps between slabs admit water, salt and foreign materials which erode the joint. Dowels, therefore, may be effective in vertical shear stress transfer, but do not limit or control the maximum joint gap width. Tie bars traditionally are deformed reinforcing bar segments that cross the joint to provide vertical load transfer and also tie the adjacent concrete slabs together so that the joint does not open. Tie bars keep adjacent slabs from floating apart, but because they provide a rigid connection, the joint cannot open sufficiently to relieve internal stresses in the concrete. The tendency of slabs to pull away from each other at the joint is typically caused by contraction of the concrete due to drying, shrinkage, thermal contraction, or the tendency of a slab to slide downhill on a sloped surface. When the joint is prevented from opening, the movement which relieves shrinkage stresses in the slabs is almost totally prevented. This results in cracking or reduced capacity of the slab to carry its intended applied loads such as vehicular traffic.